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      <div class="span12">
        <h4 id="title">Box Selection</h4>
        <p class="tags">
          <span class="badge-group">
            <a href="./index.html?q=DragBox" class="badge badge-info">DragBox</a><a
              class="badge badge-info tag-modal-toggle" data-bs-toggle="modal" data-bs-target="#tag-example-list"
              data-title="DragBox" data-content="&lt;ul class=&quot;list-group&quot;&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action active&quot; href=&quot;./box-selection.html&quot;&gt;Box Selection&lt;/a&gt;
                  &lt;/ul&gt;" tabindex="0">1</a>
          </span>
          <span class="badge-group">
            <a href="./index.html?q=feature" class="badge badge-info">feature</a><a
              class="badge badge-info tag-modal-toggle" data-bs-toggle="modal" data-bs-target="#tag-example-list"
              data-title="feature" data-content="&lt;ul class=&quot;list-group&quot;&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./vector-esri.html&quot;&gt;ArcGIS REST Feature Service&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action active&quot; href=&quot;./box-selection.html&quot;&gt;Box Selection&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./feature-animation.html&quot;&gt;Custom Animation&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./custom-circle-render.html&quot;&gt;Custom Circle Render&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./custom-hit-detection-renderer.html&quot;&gt;Custom Hit Detection Render&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./custom-interactions.html&quot;&gt;Custom Interactions&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./vector-esri-edit.html&quot;&gt;Editable ArcGIS REST Feature Service&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./filter-points-webgl.html&quot;&gt;Filtering features with WebGL&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./flight-animation.html&quot;&gt;Flight Animation&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./feature-move-animation.html&quot;&gt;Marker Animation&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./translate-features.html&quot;&gt;Translate Features&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./webgl-points-layer.html&quot;&gt;WebGL points layer&lt;/a&gt;
                  &lt;/ul&gt;" tabindex="0">12</a>
          </span>
          <span class="badge-group">
            <a href="./index.html?q=selection" class="badge badge-info">selection</a><a
              class="badge badge-info tag-modal-toggle" data-bs-toggle="modal" data-bs-target="#tag-example-list"
              data-title="selection" data-content="&lt;ul class=&quot;list-group&quot;&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action active&quot; href=&quot;./box-selection.html&quot;&gt;Box Selection&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./vector-tile-selection.html&quot;&gt;Vector Tile Selection&lt;/a&gt;
                  &lt;/ul&gt;" tabindex="0">2</a>
          </span>
          <span class="badge-group">
            <a href="./index.html?q=box" class="badge badge-info">box</a><a class="badge badge-info tag-modal-toggle"
              data-bs-toggle="modal" data-bs-target="#tag-example-list" data-title="box" data-content="&lt;ul class=&quot;list-group&quot;&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action active&quot; href=&quot;./box-selection.html&quot;&gt;Box Selection&lt;/a&gt;
                  &lt;li&gt;&lt;a class=&quot;list-group-item list-group-item-action&quot; href=&quot;./extent-interaction.html&quot;&gt;Extent Interaction&lt;/a&gt;
                  &lt;/ul&gt;" tabindex="0">2</a>
          </span>
        </p>
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          aria-labelledby="tag-example-title" aria-hidden="true">
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            <div class="modal-content">
              <div class="modal-header">
                <h5 class="modal-title" id="tag-example-title"></h5>
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        <div id="map" class="map"></div>
        <div>Selected regions: <span id="info">None</span></div>

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      <div class="span12">
        <p id="shortdesc">Using a DragBox interaction to select features.</p>
        <div id="docs">
          <p>本示例演示如何使用<code>DragBox</code>交互来选中 features 。将选中的 features 添加到选中交互(<code>ol/interaction/Select</code>) 的
            feature overlay 中，高亮显示。
          </p>
          <p>使用 <code>Ctrl+Drag</code> (<code>Command+Drag</code> on Mac)来画矩形。</p>
        </div>
      </div>
    </div>

    <div class="row-fluid">
      <h5 class="source-heading">main.js</h5>
      <pre><code id="example-js-source" class="language-js">import GeoJSON from &#x27;ol/format/GeoJSON.js&#x27;;
import Map from &#x27;ol/Map.js&#x27;;
import VectorLayer from &#x27;ol/layer/Vector.js&#x27;;
import VectorSource from &#x27;ol/source/Vector.js&#x27;;
import View from &#x27;ol/View.js&#x27;;
import {DragBox, Select} from &#x27;ol/interaction.js&#x27;;
import {Fill, Stroke, Style} from &#x27;ol/style.js&#x27;;
import {getWidth} from &#x27;ol/extent.js&#x27;;
import {platformModifierKeyOnly} from &#x27;ol/events/condition.js&#x27;;

const vectorSource &#x3D; new VectorSource({
  url: &#x27;https://openlayers.org/data/vector/ecoregions.json&#x27;,
  format: new GeoJSON(),
});

const style &#x3D; new Style({
  fill: new Fill({
    color: &#x27;#eeeeee&#x27;,
  }),
});

const map &#x3D; new Map({
  layers: [
    new VectorLayer({
      source: vectorSource,
      background: &#x27;#1a2b39&#x27;,
      style: function (feature) {
        const color &#x3D; feature.get(&#x27;COLOR_BIO&#x27;) || &#x27;#eeeeee&#x27;;
        style.getFill().setColor(color);
        return style;
      },
    }),
  ],
  target: &#x27;map&#x27;,
  view: new View({
    center: [0, 0],
    zoom: 2,
    constrainRotation: 16,
  }),
});

const selectedStyle &#x3D; new Style({
  fill: new Fill({
    color: &#x27;rgba(255, 255, 255, 0.6)&#x27;,
  }),
  stroke: new Stroke({
    color: &#x27;rgba(255, 255, 255, 0.7)&#x27;,
    width: 2,
  }),
});

// a normal select interaction to handle click
const select &#x3D; new Select({
  style: function (feature) {
    const color &#x3D; feature.get(&#x27;COLOR_BIO&#x27;) || &#x27;#eeeeee&#x27;;
    selectedStyle.getFill().setColor(color);
    return selectedStyle;
  },
});
map.addInteraction(select);

const selectedFeatures &#x3D; select.getFeatures();

// a DragBox interaction used to select features by drawing boxes
const dragBox &#x3D; new DragBox({
  condition: platformModifierKeyOnly,
});

map.addInteraction(dragBox);

dragBox.on(&#x27;boxend&#x27;, function () {
  const boxExtent &#x3D; dragBox.getGeometry().getExtent();

  // if the extent crosses the antimeridian process each world separately
  const worldExtent &#x3D; map.getView().getProjection().getExtent();
  const worldWidth &#x3D; getWidth(worldExtent);
  const startWorld &#x3D; Math.floor((boxExtent[0] - worldExtent[0]) / worldWidth);
  const endWorld &#x3D; Math.floor((boxExtent[2] - worldExtent[0]) / worldWidth);

  for (let world &#x3D; startWorld; world &lt;&#x3D; endWorld; ++world) {
    const left &#x3D; Math.max(boxExtent[0] - world * worldWidth, worldExtent[0]);
    const right &#x3D; Math.min(boxExtent[2] - world * worldWidth, worldExtent[2]);
    const extent &#x3D; [left, boxExtent[1], right, boxExtent[3]];

    const boxFeatures &#x3D; vectorSource
      .getFeaturesInExtent(extent)
      .filter(
        (feature) &#x3D;&gt;
          !selectedFeatures.getArray().includes(feature) &amp;&amp;
          feature.getGeometry().intersectsExtent(extent)
      );

    // features that intersect the box geometry are added to the
    // collection of selected features

    // if the view is not obliquely rotated the box geometry and
    // its extent are equalivalent so intersecting features can
    // be added directly to the collection
    const rotation &#x3D; map.getView().getRotation();
    const oblique &#x3D; rotation % (Math.PI / 2) !&#x3D;&#x3D; 0;

    // when the view is obliquely rotated the box extent will
    // exceed its geometry so both the box and the candidate
    // feature geometries are rotated around a common anchor
    // to confirm that, with the box geometry aligned with its
    // extent, the geometries intersect
    if (oblique) {
      const anchor &#x3D; [0, 0];
      const geometry &#x3D; dragBox.getGeometry().clone();
      geometry.translate(-world * worldWidth, 0);
      geometry.rotate(-rotation, anchor);
      const extent &#x3D; geometry.getExtent();
      boxFeatures.forEach(function (feature) {
        const geometry &#x3D; feature.getGeometry().clone();
        geometry.rotate(-rotation, anchor);
        if (geometry.intersectsExtent(extent)) {
          selectedFeatures.push(feature);
        }
      });
    } else {
      selectedFeatures.extend(boxFeatures);
    }
  }
});

// clear selection when drawing a new box and when clicking on the map
dragBox.on(&#x27;boxstart&#x27;, function () {
  selectedFeatures.clear();
});

const infoBox &#x3D; document.getElementById(&#x27;info&#x27;);

selectedFeatures.on([&#x27;add&#x27;, &#x27;remove&#x27;], function () {
  const names &#x3D; selectedFeatures.getArray().map((feature) &#x3D;&gt; {
    return feature.get(&#x27;ECO_NAME&#x27;);
  });
  if (names.length &gt; 0) {
    infoBox.innerHTML &#x3D; names.join(&#x27;, &#x27;);
  } else {
    infoBox.innerHTML &#x3D; &#x27;None&#x27;;
  }
});
</code></pre>
    </div>

    <div class="row-fluid">
      <h5 class="source-heading">index.html</h5>
      <pre><code id="example-html-source" class="language-markup">&lt;!DOCTYPE html&gt;
&lt;html lang="en"&gt;
  &lt;head&gt;
    &lt;meta charset="UTF-8"&gt;
    &lt;title&gt;Box Selection&lt;/title&gt;
    &lt;link rel="stylesheet" href="node_modules/ol/ol.css"&gt;
    &lt;style&gt;
      .map {
        width: 100%;
        height: 400px;
      }
    &lt;/style&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;div id&#x3D;&quot;map&quot; class&#x3D;&quot;map&quot;&gt;&lt;/div&gt;
    &lt;div&gt;Selected regions: &lt;span id&#x3D;&quot;info&quot;&gt;None&lt;/span&gt;&lt;/div&gt;

    &lt;script type="module" src="main.js"&gt;&lt;/script&gt;
  &lt;/body&gt;
&lt;/html&gt;</code></pre>
    </div>

    <div class="row-fluid">
      <h5 class="source-heading">package.json</h5>
      <pre><code id="example-pkg-source" class="language-json">{
  &quot;name&quot;: &quot;box-selection&quot;,
  &quot;dependencies&quot;: {
    &quot;ol&quot;: &quot;8.2.0&quot;
  },
  &quot;devDependencies&quot;: {
    &quot;vite&quot;: &quot;^3.2.3&quot;
  },
  &quot;scripts&quot;: {
    &quot;start&quot;: &quot;vite&quot;,
    &quot;build&quot;: &quot;vite build&quot;
  }
}</code></pre>
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